Alkyd resin-diisocyanate cellular foamed plastics



Patented Apr. 8, 1952 ALKYD RESIN-DIISOCYANATE CELLULAR FOAMED PLASTICS Eli Simon, Los Angeles, and Frank W. Thomas,

Burbank,. Calif, assignors to Lockheed Aircraft Corporation, Burbank, Calif.

Application February 17, 1949, Serial No. 77,058 V 24'Claims. (Cl. 260'-2.5)

N Drawing.

' i This invention relates to foamed cellular plastics--and relates -more particularly 'toimproved cellular-plastics incorporating thermoplastic filmformi-ng resinousadditives which serve as foam stabilizers during thefoami-ng reaction of the alkyd resin-diisocyanate mixture.

our copending applications, Serial No. 35,294 filed June 25, 1948, now Patent 2,577,279,; Serial No. 44,993 filed August 18, .1948, now abandoned; Serial No. 50,007 filed September 18, 1948,- now Patent 2,577,280. and Serial No. 54,822 filed October 15Z,"-1948',TnUW"P8JtIlt 2,577,281, we have disclosed several methods and formulationsfor making low densitycel'lular foamed plastics of such character that the component ingredients are simply mixed togetherandpouredinto a cavity to. react at atmo'spherlc pressure to assume the cellular condition, The formulations included in ourlcopending applications are. primarilysystems comprising alkyd resin, metatoluene diisocyanate and water and we obtained effective foaming action by controlling .thezwater content and/or by theemode in which the water is incorporated in the reactantlmixture and/ or by the. employment of additives such .asmetallic leafing. powdersrand metallic soap powders.

We have. discovered that. the. incorporation, in thealkyd resin-diisocyanate systems,.of a high molecular. weightfilmdonning polymeric thermoplastic. resin additive vavoids'the necessity of using 'te'r'mixture, =it is-important to 1 properly :relate or balance the rate of blow or expansion and the rate of cure. The. foaming mass must possess sufficient plasticity to expand by the liberated gas of the reaction otherwise the cells will not form.

. However, if the mass does not have sufficient elasticity the freshly formed gas cells collapse and an adequate volume of foamis not obtined. In the event of such cell collapse the gasescapes through the mass so that-'-the pressure essential to the expansion of the mass is lost. Thus-there must ,bera balance between the. decrease in plasticity landl the. increase .in elasticity. The. foam. stabl lizing resin additive of the invention, when used in the foaming reactant mixture, maintains adequate cell wall rigidity and elasticity while there is alsothe high plasticity essential to maximum expansion, thereby reducing or eliminating cell collapse and assuring the formation of strong, light-weight foamed plastics.

' Another object of the invention is to provide alkyd resin-diisocyanate foaming plastic formulations of the class referred to incorporating high molecular weight polymeric resin additives which permit the employment of a higher water content thereby favoring the production of lower density foamed plastics.

Another object of the invention is to'provide alkyd-resin-diisocyanate-water formulations of the class referred to wherein the high molecular weight thermoplastic polymeric resin additives promote the production of foamed plastics having very small uniform cells and having greater compression strength, tensile strength, and shock and vibration resistance characteristics.

Another object of the invention is to provide a foaming cellular plastic material of the character referred to in which the high molecular weight thermoplastic polymeric resin additives increase the elasticity of the foaming mass during the critical curing stage thereby relieving internal stresses and minimizing or preventing cracking, especially in foamed masses of large cross section.

A further object of the invention is to provide a cellular foamed plastic material of the class above referred to in which the high molecular weight thermoplast c polymeric resin additive assists .in'stabilizing the reaction and increases compatibility of the diisocyanate with the alkyd resins so that there is less mixing time required and less tendency for premature reaction.

Other advantages and features of the invention will become apparent from the following detailed description of several typical formulatio and their procedures.

The invention provides, generally, the prepara-, tion or mixing of an alkyd resin, a diisocyanate and a high molecular weight thermoplastic polymeric resin additive and the subsequent pouring or application of the mixture to react at atmospheric pressure with or without the application of external heat and with or without a postcuring at somewhat elevated temperatures. Further, the invention comprehends, when desired, the incorporation in the reactant mixture of flame retardant additives, metallic soap powders or metallic leafing powders. As will be later .de

3 scribed, the fire retardant and flame proofing additives which we prefer to employ, additionally serve to materially increase the volume of the cellular foamed plastic material and the inclusion of the metallic soap powders or the metallic leafing powders may result in superior products.

The alkyd resins which we preferably employ are the reaction products of polyhydric alcohols and polybasic acids unmodified or modified with oil and/or other resins, the alkyd resins having an acid number of from to 80, a Water content of from 0.1% to 5% by weight, and having the following ratio range of the hydroxyl groups to the carboxyl groups in the alkyd resin reactants: from 3 hydroxyl (OH) :1 carboxyl (COOH) to 4' hydroxyl (OI-I) :5 carboxyl (COOH).

We have found it preferable to employ alkyd resins having an acid number between approximately and approximately 25 and wherein the ratio of the hydroxyl groups to the carboxyl groups is 2 to 1. However, satisfactory results are to be obtained by employing resins having the foregoing ranges of acid numbers and ratios of the hydroxyl to the carboxyl groups in the alkyd resin reactants. The following formulae are suitable for the preparation of unmodified alkyd resins from polyhydric alcohols and polybasic acids.

Formula A Mols Glycerol 4 Adipic acid 2.5 Phthalic anhydride 0.5

Formula B Glycerol 2 1,4 butylene glycoL 1 Adipic acid; 2

Formula C Mols Trimethylol propane 4 Adipic acid 2.5 Phthalic anhydride 0.5

Excellent results have been obtained by employing the resin of Formula A having an acid number of 16 and a water content of 0.56% by weight and by employing the resin of Formula C having an acid number of 20 and a water content of 0.85% by weight. The ratios of the hydroxyl groups to the 'carboxyl groups of the alkyd resin reactants in Formulae A, B, C, and D are respectively 2(OH) :1(COOH), 2(OH) :1(COOH), 2(OH) 21(COOH), and 1(OH) :l(COOH).

The following Formulae E, F and G are typical or representative of formulaev for preparing unmodified alkyd resins from single polyhydric alcohols and singlepolybasic acids producing resins suitable for use in the method andproducts of the invention:

Formula E Mols Glycerol 4 Adipic-acid 3 a Formula F Mols Trimethylol propane 3 Phthalic anhydride 2 4 FormulaG Mols Glycerol 1 Phthalic anhydride 1.5

The respective ratios of the hydroxyl groups to the carboxyl groups of the alkyd resin reactants of Formulae E, F and G are 2(OH) 21(COOH), 9(OH) :4(COOl-I) and 1(OH) :1(COOH).

Formulae H and I are examples of alkyd resins, oil modified, that have been found to be practical and operative in preparing the foamed cellular plastic materials in accordance with the present invention. The respective ratios of the hydroxyl groups to the carboxyl groups in the alkyd resin reactants of these formulae are 3(OH) :3 (COOH) and 6(OH) :7(COOH) Another example of an oil modified alkyd resin which we have found to be practical and effective in preparing the foamed cellular plastic material is found in Formula J where the ratio of the hydroxyl and carboxyl groups of the alkyd resin reactants is 10 (OH) :9(COOH) and where the (OH) group in the ricinoleic acid, or the 3(OH) groups for the castor oil molecule, is taken into account or l (OH) :9(COOH) when the (OH) groups in the ricinoleic acid is not considered.

Formula J Mols Glycerol 2.5 Adipic acid 4 Castor oil 1 Maleic anhydride /2 An example of a natural resin modified alkyd .resin suitable for incorporation in the cellular foamed plastics of the invention is set forth-in Formula K where the ratio of the hydroxyl to the carboxyl groups of the alkyd resin reactants is 1(OH) :1(COOH).

Formula'K Glycerol gram mol 1 Sebacic acid gram mol 1 Resin copal gram-.. 100

An example of a synthetic resin modified alkyd adapted for use in the formulations and method of the invention is set forth in Formula L where the ratio of the hydroxyl groups to the carboxyl groups of the alkyd resin reactants is 3(OH) :2(COOH) Formula L Phenol 50 grams Formaldehyde 17 grams Rosin 65 grams Phthalic anhydride 30 grams or 0.2 gram mol Glycerol 18.4 grams or 0.2 gram mol p onent or-eomponents-of the reactant foamprod-ucing mixtureaisirom 0.1% to 5% by weight, j irrespective-ofthe' specific manner 'of incor- -porating the water in the mixture. In the f ormulae and examples -hereinset forth, it

reactant mixture may be -incorporated:thereinin wombination with a non-ionic wettingagentzor theuseiof: one or more metallic salt hydrates. Thetpolyisocyanate employed..in .preparing:the a eactantcellularfoam.producingmixture-is prefrably. metaetoluenel-I diisocyanate. Theumetatoluene: diisocyanateais. used; in..tl'1e. proportion of f-=rom 35.--to 3150.. grams for. each 100 gramslofcthe allcvd resin.

As :mentioned. .1 above and as i describedin; our co'pen'ding: application Serial No. 50,007.,the incluwsion of a: selected; proportion :of. a: metallic .1soap powders in thereactantmixture produces superior :results. The .metallic. soap apowders. which .we -=rhave.- found.- to bepractical and :efiective :in the lformulations sof the invention are metallic .soap -:-powders-'oflfatty acids havingirom 12 to 20 car- -bon atoms. Includedamongsuch metallic 'soap -powders are: :zinc stearate, aluminum- 1 stearate, -calcium stearate-,=magnesium stearatamagnesium f-h'yd-roxy-stearate,-barium stearate, zinc laurate,

al'cium oleate, strontium stear-ate. The proporion of -the= metallic-soap powder employed may mange from to 7 -grams'of the selected metal- '--;lic'-soap-'p'owder for each 30 g-rams ot'the "alkyd ---res1n. r r v fit his beenfoundthat the;-inclusion of metallic leafingpowdersin the alkyd resin ;polyisocyanate hi ghf-mole cular' weight-mesin mixture results in foamedcellulargplastic products of superior sical properties. Our-copendi-ng application, 1al -1Io: 44,9931d6501ibe3""the use of such me- 'j t ic lea-ring powders in the alkyd ;resin-polyiso cyanate reactant mixtures. :The "metallic leafing ow'ders employed; mustyhave the proper-ty of p: fipg whensuspendedyin a liquid vehicle-and when so suspended and applied, as a paint, have the ability of forming a conti'nuousjfilm, on the nreierte ithatthe e auic, leafing wde s b sdi i r sometime a t man fa t e and p io .ftcrinclusi nfl nt e e c an xtures of jthe nvention; The metallic leafing powders which .we have found to be practical and effective in the formulations of the invention include: aluminum leafingpowder aluminum bronze leafing powder, 'g'old bronze leafing powder copperbronze leafing powder, lead leafing powder, nickel leafing powder, silver leafing powder, gold leafing powder, copper leafing powder, stainless steel leafing powder (18:8 chromium-nickel). ,The metallic leafing powders employed individually or in suitable mixtures may beused in the proportion of from I; to 7 /2 grams foreach 30 grams of the alkyd ,,resin in the polyisocyanate-alkyd resin reactant mixture. Good results have been obtained by =employing aluminum leafing powder ofsuch finee -nesstthat not more than2 is retained on a nume-ber 325 sieve and by employing aluminum bronze wleafing powder, gold bronze leafing powder and oopperbronze leafing powder of such fineness that not more' than' 03% is retainedzon. arr-min berlOO sieve.

Excellent results are obtained when botlrs-a metallic soap powder and a metallicleaflngpowder are incorporated in'the polyisocyanateealkyd resin-high molecular.v weight 5 thermoplasticzaresin mixture. The-combination 20f. suchifillers rappears to act synergistically, that is the combina tion of the metallic soap powder and. theimetal lic leafing powder causes the formation of a greater volume of the cellular plastic than if the same proportionate quantity of each individual filler is used separately in the identical polyiso- .cyanate-alkyd resinhi h. molecular weight there- ;;moplastic.resin mixture. When both the metallic leafing powders and the metallic soap powders ;are usedin the formulationsofthe-inverrtion, the metallic leafing powder maybe employedinthe -wproportionp om1 g to 5 ram i n each- 30 grams of the alkyd resin andthe metallim may beused in the proportion of..from tq5 5 surfaceofrthe applied liquid vehicle or paint. It s grams for each gram-0f the alkyd resin.

The foamed cellular plastic productsofnthe invention may be made flame resistantand .self- 2. Bis(methal1y1) benzenephosphonate cH,=c-cm o-1 o-c1ar o=om Q m um and,

3. Diallyl :toluene phosphonate These additives. not only senvel.,to,. impart rfla'me resistance and decrease flame propagation characteristics to the roamed cellular .plasticnpltodnot but also unexpectedly, serve to .material-lyrde crease the density of thefoamedmaterial. .;..',lhe

proportion of the selected fire retardantfland flame-proofing additive employedin the polyisocyanate-alkyd -resin reactant mixture may1,=be

varied. considerably, but in practice. from -l i;gr.a.m

to.20 grams. of the. additive may be usedwith each 30 grams of the alkyd resin. :'It' is} usually the foamed plastic are of smaller size.

-' retardant and flame-proofing agents include trichloralkyl phosphates of the general formula .where R1, R2 and R3 are alkyl groups having from 2 to 4 carbon atoms, antimony oxide $1320: and unsaturated alkyl esters of the alkenyl phosphonicacids of the class described in United States Letters Patent No. 2,425,766 issued August 19, 1947, namely compounds having the general formula R R CZCR PO(OCH2CRICHR )2 where R,

R and R are hydrogen or alkyl, and R and R are hydrogen, alkyl or aryl radicals.

Examples of the tri-chloralkyl phosphates which we have found to be efiective in the formulations of the invention are:

Examples of the unsaturated alkyl esters of alk'enyl phosphonic acids which we have found to be practical and effective in the cellular plastic formulations are:

Diallyl isobutene phosphonate H H H crn=0-oH,oP-0-0H,-o=cm =C-CH; H

diallyl styrene phosphonate ture reaction, prior to pouring, due to long mixingtime... This is important as it permits the utilization of higher water content alkyd resins which, in turn, can result in a lowered density of the foamed plastic product. The antimony oxide, in addition to serving as a flame-proofing agent, acts as a cell size regulator whereby the cells of The unsaturated alkyl esters of alkenyl phosphonic acids may be used in the proportion of from 1 to 20 grams for each 30 grams of the alkyd resin when employed without the unsaturated alkyl esters of aryl phosphonic acids previously named. The trichloralkyl phosphates may be used in the proportion of from /2 to grams for each 30 grams of the alkyd resin and when used with the unsaturated alkyl esters of aryl phosphonic acids in the proportion above named may be used in the proportion of to 7 grams for each 30 grams of the alkydresin; The antimony oxide may be used in the'proportionof from to 5 grams for each 30 grams of the alkyd resin with or without the addition of the unsaturated alkyd esters of aryl phosphonic acids or the trichloralkyl phosphates.

' The present invention is characterized by the inclusionin' the reactant mixture of one or more high molecular weight thermoplastic film-forming polymeric resin additives. These additives stabilize the foam during the reaction, permit the use of higher water contents, increase the elasticity of the cell walls during the foaming and perform other functions productive of low density cellular plastics having superior physical properties. The resin additives are soluble in V meta-toluene diisocyanate and may or may not 'react with the meta-toluene diisocyanate.

The following resin additives have each been found to be practical and effective in the alkyd resin-diisocyanate reactant systems and when employed in the concentration ranges set forth, do not depend for their action upon the presence of other addi- -.tives such as the metallic soap powders, the

metallic leafing powders or the flame retardants. which latter additives may or may not be included in the alkyd resin-meta-toluene diisocyanate mixture depending upon the intended character of the products and their intended uses. In general,

a concentration of the high molecular weight polymeric thermoplastic resin additives of approximately 2 grams for each 100 grams of the meta-toluene diisocyanate gives excellent results, it being understood that the concentrations or proportions of the individual additives depend to a considerable extent upon the nature of the particular additives. The film-forming and foam stabilizing resin additives which we employ in the reactant foamed cellular plastic formulations include: ethyl cellulose, polymeric chlorinated natural rubber, benzyl cellulose, natural rubber, polymeric vinyl chloride-vinyl acetate co-polymers, polyvinyl chloride, polyvinyl acetate, polystyrene, polydichlorostyrene, polymeric acrylate and methacrylate resins and their co-polymers, polyvinyl butyral.

Ethyl cellulose, which we have found to be particularly desirable in the formulations of the invention, is a cellulose ether obtained by the reaction of ethyl chloride with alkali cellulose as follows:

RON a ClC2H5 ROC2H5 NaCl where R represents the cellulose radical. From the structure of the native cellulose H OH HrOH 570 it is seen that each glucose unit has three replaceable OH groups, all or some of which may react as above to form the ether linkages. The molecular weight of ethyl cellulose is high since a cellulose molecule, having 570 recurring glucose units, a molecular"; weight of about-1 0,000.

Very' satis'factory:resultshave been obtained using commercialgrades of ethyl cellulose resins where 1 inthe-substitution valusare between 2.15 and 2.60 ='ethoxyl-- groups for each glucose unit, that; is where the ethoxyl content is from 43% to 50%."

Thempreferredethoxyl content range "or the ethyl celluloseresin is from45.0 to 49.5%; 1 The propertion or; concentration of the ethyl cellulose in the reactant alkyd resin-meta-toluene diisooyanate' systems of the inventioniis from 0.03gram to grams of the ethyl cellulose for each 100'gramsi of the meta-toluene diisocyanate, the preferred concentration of the ethyl cellulose being between /2 to 5 grams foleach 100 grams of the meta toluene diisocyanate; Very low concentrations of the ethyl cellulose are 'efiective in'producing low densityfoamed plastics having smal1-uniformj cells and superior physicalcharacteristics. We

believe that'the particularly excellent results ob'- tained with only small concentrations of the ethyl ic'ellulose are accounted for,at least in part, v by the rea'ction of the ethyl. cellulose with the meta-toluene diisocyanate through addition poly-7i merization between'the labile hydrogen atoms of l the free OH) 'groups. in the ethyl cellulose mole; cules and the 'isocyanate groups producin sol a ble, very high molecular weight reactive poly-;.- isocyanates;- Such' a reaction is illustratedas"- in-toluene diisbcyanatd (excess used) M H ta With the extremely :low. efiective concentrationsof the ethyl cellulose, for example 0.03 gramof the ethyl cellulose resin per 100 grams of the meta-toluene diisocyanate, it is evident that there is substantially no increasedn viscosity of the mixture, particularly where low viscosity ethyl cellulose i's used. 1 The effect of'theethyl cellulose is, therefore'g not*to-be"ascribed to" a viscosity increase but appears to v be due to reinforcement and stabilization of thecells-of the foaming re actant mixture preventing collapse of the cells 1 and consequentloss of gaszpressure. 1 'I'h'is is substantiated. by the fact that an increase-inviscosity' of the reactant mixture by dissolving low molecular weight resins and particularly those; that are n0t predominantly linearsuch-asester:

gum or glycerol abietate, in the foaming mixture witlLthe-ioam stabilizers such as metallic-soaps metallic lea-fling powder, omitted ,doesnotavoid cell collapse but results in a condition where Benzoyl peroxidelflsmi l cellcollapse predominates due to insufiicient .ce1l.

reinforcement so that practically lndpla'stic i f 0 am volume is "obtained. The viscosity "of" the ethyl?" celluloselresins which 'we "employis between fl E and 200 centipdises, and preferably 'between"50'i and 100 centipoises,-the viscosity beir1g"'deter=' mined on a 5% by weight'solution in a 60:40 tolune-ethenol solvent at 25 C.

Thlfollo'wing'" are typical preferred" formuia tent (ef -the alkyd: resin constituent m'ay rang from 0.1 by weight to 5.0% by weight, excellent results having been obtainedI' Where the water contentof the alkyd resin was as indicated and also at-l%, 1.5-%, 2% and-3.5% by-weight.

Eaiample 2 If V Grams Alkyd iesin Of' -FO'Imula- C having an" acid numbe oi -20 and -a water content of r Meta-'toluene lidiisocyanate containing gramsethyl-celluloseg havirig a viscosity of 7 centi-poises -and-having anethexyl contentof---rom-- 46.3 to "48i5"%,7 pen- 100 grams of -the-meta-toluene diisocyariatm 40 Diallyl phenyl phosphonate 10 Benzoyl peroxide 0.50

The formulation of--Example-2 may be varied by employing an ethylcellulos'e resin having a viscosity of as high as approximately 200 centipoises, although preferably the ethyl fcellulose 1 resin has a centipoise viscosity of from to 100 and an ethoxyl content of from 45.0% to-49.5%.

Example? 4 Alkyd resin of Formula C having an' acid I nu'm-ber "0120' and a water content'of f 0.85% by weight; Meta-toluene diisocyanate containing 0.03

gram ethyl cellulose, having a viscosity T of 7 centipoises-and an etho'xylcontent of from 46.8% to 48.5%, per IOOgrams of meta-toluene diisocyanate 40 Diallyl phenyl phosphonatenu 10'1" Benzoyl peroxide In the formulation of'E xample'3 excellent results have been obtained when the ethyl cellulose resin was of 1-00c'enti'poises viscosity and had an ethoxy-lcontent of from-48.0 to 49.5%;

Example 4 Grains Alkyd resin "of Formula C having an acid number of ZOa-nd' a water content of 0.85% "by weight). 60

Meta-toluene diisocyanate containing l0' grams of ethyl cellulose, having a viscos= ity of centipoises and an ethoxyl content of from 48.0% to 49.5%,"per 100 grams of the meta-toluene diisocyanate- 40' toluene diisocyanate 40 Diallyl phenyl phosphonate 40 Benzoyl peroxide 2 In Example, 5, the concentration of the diallyl phenyl phosphonate may be reduced to 20 grams in which case 1.0 gram of benzoyl peroxide is employed, or the concentration of the diallyl phenyl phosphonate may be reduced to 30 grams in which case 1.5 grams of benzoyl peroxide is used.

Example 6 Grams Alkyd resin of Formula C having an acid number of 20 and a water content of 0.85% by weight '60 Meta toluene dlisocyanate containing 2 grams of ethyl cellulose, having a viscosity of 100 centipoises and an ethoxyl content of from 48.0% to 49.5%, per 100 grams of the meta-toluene diisocyanate 40 Zinc stearate 3 Diallyl phenyl-phosphonate Benzoyl peroxide 0.5

Example 7 Grams Alkyl resin of Formula C having an acid number of 20 and a water content of 0.85% by weight Meta-toluene diisocyanate containing 2 grams of ethyl cellulose, having a viscosity of 100 centipoises and an ethoxyl content of from 48.0% to 49.5% per 100 grams of the metatoluene diisocyanate 40 Zinc stearate 3 Aluminum leafing powder In Examples 6 and '7, the concentration of the zinc stearate powder may be reduced to gram while the concentration of the aluminum leafing powder may be increased to either 1 fram or 2 grams when employed with the gram of the zinc stearate powder.

Diallyl phenyl phosphonate 10 Benzoyl peroxide 0.5 Zinc stearate powder A; Aluminum leafing powder -i 4 The formulation of Example 8 may be modified by omitting the metallic leafing powder andby employing 1 gram of the zinc stearate powder. Example 8 may also be modified by increasing the water content of the alkyd resin constituent to 0.75% by weight and by employing 2 grams of the zinc stearate powder while omitting the aluminum leafing powder.

To demonstate the efiectiveness of the ethyl cellulose resin additive the following constituents may be mixed together and poured into a cell or mold 6 high, 6 long and 1" wide, maintaining the mold at a temperature of about Grams Alkyd resin of Formula C having an acid number of 20 and a water content of 0.85% by weight 60 Meta-toluene diisocyanate 40 Diallyl phenyl phosphonate 10 Benzoyl peroxide 0.50

It will be found that this mixture will rise about 1 inch in the mold cavity, giving practically no foam value and resulting in a product having a calculated density of approximately 70 lbs. per cubic foot. However, by repeating this identical procedure with the exception of adding 2 grams of ethylcellulose of 100 centipoise viscosity and from 48% to 49.5% ethoxyl content for each 100 grams of the meta-toluene diisocyanate employed, it will be found that the mixture will yield a uniformly foamed cellular plastic having pin-point size cells and having a density of approximately 8.5 lbs. per cubic foot. A foamed plastic made in accordance with Example 2 and having a density of approximately 8.50 lbs. per cubic foot had an average compressive strength of 270 lbs. per square inch at 80 F. and 182 lbsfl per square inch at 165 F. and had an average shear strength of approximately lbs. per square inch at 80 F. and 110 lbs. per square inch at F. Uniformly foamed cellular plastics having excellent physical characteristics are obtained with the other fromulations given above having densities as low as 3 lbs. per cubic foot.

In the formulations of the invention incorporating ethyl cellulose and including one or more metallic leafing powders as foam stabilizers, the concentration or proportion of the ethyl cellulose may be varied to control the cell-size of the foamed cellular plastics. This may be desired or important where the cellular plastics are to be used for ornamental or decorative purposes. In such formulations very small amounts of the ethyl cellulose may be used and gradations in the amount of the ethyl cellulose result in foamed cellular products having cells of different sizes. Examples 8-A, 8-B and 8-C illulstrate this.

Example 8-A from 48.0% to 49.5% 0.005 Copper leafing powder 2 Diallyl phenyl phosphonate 5 Benzoyl peroxide A The approximate cell size of the cellular plastic produced from Example 8-A is 1%;

ameter.

inch in di-- 1s Eaiample 8 B Grams I Alkyd-resin or Formula having an acid' number of 20and 'a water contentof 2% by weight 30 Meta-toluene diisocyana'te fle 20 Ethylbellulose having a centipoise viscosity of 100- andyan ethoxyl content of from I 48.0% 'to' 49.5% 0.01 Copper-leafing-powder:; 2 Diallylphenyliphosphonateri 5 Benzoyl'peroxide The cells of. thefoamed plastioofn-Exa-mple 8- 13 havea diameter of about fi 'inche- Example -8-C 3 n Grams Alkyd resin of Formula C'having an acid number of.. and a Water content of 2% V by weight "1. ":1 Meta-toluene diisocyanate' 20 Ethyl cellulose having a centipoise 'vis-x cosityof 100 and. an ethoxylcontentzoff from ,48;0%"ito149.5% 0.015 Copper le'afing powder .2 i Diallyl phenyl. phosphonate a 5 Benzoyl; peroxide A The-cel1s in this case have a diameter-0f fromv approx-ima-tel' /32 to /64 inchw In these formula? tions-it willbe noted that only-very minorproz- H The chlorinatedarubber is usually produced-tohave .this(67%, chlorine content but is available in-iseveraltviscositytypes; thoseof higher viscosity' having,--larger; molecules. 1 The viscosity designateg H v This classDi co-polymers:maylberepresented ase 142% i Natural rubber (polymeric isopreneayz,me hane represented by: i n

our formulations contain aapproxi'mately 87% I vinyl chloride and (13% avinyl acetate iandxzhay molecular weights/of between-.6900 and- 25,000

It has also been -"f0iind tha't such co-polym 'ers containing *from-- 90 to v 95 eviiiyrchleride are a1so practical 'andoperative -in our 'celi'i'lar'fi able for use in our invention have.x.moleoulai'a=" tions-of; the chlorinated rubber are in-centipoises i Polydichl'orostyreneis representedbyr;

a Thepoly-vinyl chloride -as employed-h the foamed plastic formulations? The polyvinyl 1acetatesawhich are obtainedsby thepolymerization of vinyltacetatelthat areasu' -.t-t

weights ranging from 10,000 to 50,000'."

acta'rit 'ioam'=-producing *mixture has =a "-ave'ra molecular-- weight ofabout 5,000 -"arid* 1's repre sented by The polymericvacrylate andimethacrylateiresinsi l and their ,copolymers,.- prepared by polymerizing the lower esters of acrylic and methacnyliciacid,

are further examples ofihignrmoleoularivy/eight?" thermoplastic --resins adapted *:-torbe:--employeel as film forminga andr foam /stabilizing\additivesrin the reactant mixture Thse:includer'rpolymers of the following esters 1 (a)' Methyl methacrylate,

(c) Isobutyl:methacrylate wv '(e) Co-polymer of methyl acrylate and ethyl methacrylate:

OH: H H I OH;=CCOCHu CHi= fi-OC2H5 Methyl acrylate Ethyl methacrylate CHa H H H L u-O-o a viscosity of 10 centipoises per 100 grams of the meta-toluene diisocyanate 40 Diallyl phenyl phosphonate 10 Benzoyl peroxide In the formulation of Example 9 we have found that foamed cellular plastics'of good physical properties and of low density are obtained when the viscosity of the chlorinated natural rubber is 20 centipoises, 143 centipoises and 980 centinoises.

Example 10 I Grams Alkyd resin of Formula C having an acid 1 number of 20 and a water content of 0.85% by weight 30 Meta-toluene diisocyanate containing 2.5 grams chlorinated natural rubber of 980 centipoises viscosity per 100 grams of 'meta-toluene diisocyanate 20 Diallyl phenyl phosphonate Benzoyl peroxide 0.25

The benzyl cellulose, when employed as a filmforming and cell stabilizing resin additive in the alkyd resin-diisocyanate reactant mixture, is used in the concentration of from V to grams for each 100 grams of the meta-toluene diisocyanate. The following is a typical example of the invention incorporating benzyl cellulose as a resin additive:

Example 11 Grams Alkyd resin of Formula C having an acid number of 20 and a water content of 0.85% by weight 60 Meta-toluene diisocyanate containing 4 grams of benzyl cellulose per 100 grams of the meta-toluene diisocyanate 40 Diallyl phenyl phosphonate 10 Benzoyl peroxide When the polymeric vinyl chloride-vinyl acetate co-polymer is used as the "resin additive in the alkyd resin-diisocyanate reactant mixture the concentration of the co-polymer may be from to 10 grams foreach 100 grams of the metatoluene diisocyanate. It is preferred to employ a ,vent resistant material.

16 co-polymer containing approximately 87% vinyl chloride and approximately 13% vinyl acetate. The following is a typical formulation incorporating such a co-polymer as the resin additive.

Example 12 Grams Alkyd resin of Formula Chaving an acid number of 20 and a water content of 0.85% by weight 60 Meta-toluene diisocyanate containing 4 grams of the polymeric vinyl chloridevinyl acetate co-polymer for each 100 grams of the meta-toluene diisocyanate- 40 Diallyl phenyl phosphonate 10 Benzoyl peroxide 2 Excellent results have also been obtained by reducing the concentration of the polymeric vinyl chloride-vinyl acetate co-polymer in Example 12 to 2 grams of the co-polymer resin for each 100 grams of the meta-toluene diisocyanate.

Likewise, satisfactory results have been obtained in the formulation of Example 12 where the co-polymer contained from 90% to vinyl chloride.

As described above, polyvinyl chloride, polyvinyl acetate, polystyrene and polydichlorostyrene are suitable as the high molecular weight thermoplastic resin additive and good results have been obtained by employing these resins in the formulation of Example 11 in substitution for the benzyl cellulose. Likewise, polymeric methyl methacrylate has been found to be suitable as the resin additive of Example 12 in place of the co-polymer resin when used in the proportion or concentration of 2 grams for each grams of the meta-toluene diisocyanate. In Examples 9 through 12, employing the resin additives named therein and the resins just mentioned, foamed cellular plastics of uniform structure and of a density of approximately 8 lbs. per cubic foot are produced. It will be observed that in these examples and with these resins, the metallic leafing powders and the metallic soap powders have been omitted and yet excellent results are obtainable, it being understood that the metallic leafing powders, the metallic soap powders and/or the above described flame proofing additives may be incorporated in the formulations if desired.

In carrying out the method in the production of foamed cellular plastics, the selected ingredients are simply mixed thoroughly in the ratio designed to produce a foamed plastic having the desired density and physical characteristics and this mixture is then poured into the mold or cavity in the structure in which it is to form a part or is applied to a structural surface or the like. The reactant mixture is allowed to react at atmospheric pressure either with or without the application of external heat or attended by a moderate heating of, say, between F. and 150 F. depending upon the size of the batch, etc. The reaction is permitted to go on to completion to produce the foamed cellular product. The cellular foamed plastic product may then be subjected to a post-curing of from 10 to 20 hours at a temperature of from F. to 225 F. to continue the polymerization of the reaction and thus obtain a stronger, more heat stable and more sol- The plastic will firmly and uniformly adhere to the surfaces of practically any solid material during the foaming reaction and is thus particularly well suited for use in laminating operations and where it is de- ;sired to provide a low density filler or core material otgood strength characteristics which adheres :to thegsurfaces which it contacts. Asabove pointed out, :the foamed zcellular plastic material has extremely small or pin-point size cells "that are substantially spherical and that are noncommunicating, theseycel-ls being uniformly distributedthroughout .thexentireimass.

.It should be understood that the invention is not based upon or dependent upon-the theories which we.liave expressed. Noris theinvention to be regarded aslimited to the express procedure or materials set forth, these details being given only-by way of illustration and-to aid in-clarifying the invention. We do not .regardsuchspecific details as essential to the invention except insofaras they are expressed by way-of limitation in the following claims (in whichit is our intention to claim .all :novelty inherent inthe invention as broadly as is permissible vfin view of 'the prior .art.

'We claim:

1. HA cellularreactlon productofan alkyd resin having a water content of from.0.l'% to "5% by Weight, .an ,acid number of from "5 to I80 and wherein thehydroxyl and carboxyl groups of the alkyd resin reactants arein the ratio range of from;3('OH) 2.1!(COOH) to Atom :iSICOOI-I), from 35 to 150 ,parts lby'weight of meta-.tdluenediisocyanate for each 100 partsf by weight of said resin, and from 0.0.3 to '15 parts by weight for each 100.,parts of the me'ta toluene diisocyanate of ethyl cellulose .soluble in meta-toluene diisocyanate .andlhaving a centipoise viscosity of between "7. and 200, the viscosity of the ethyl cellulose being determined on a 5% by weight solutionlfin 'a 60 :40 toluene-ethanol solvent at 25 C.

2. The cellular reaction product of, "on an approximate weight basis; ana'lkyd resin having'a water content of from'0;1% to 5% by weight prepared from 4 mols trimethylol propane, 2.5 mols adipicacid and"0.5 m'ol phthalio anhydride and having'an acidnumber offromb to 80;'from 10to IO-grams of meta-toluene "diisocyanate foreach 30 grams of said alkyd resin, from :03 to "15parts by weight of ethyl cellulose soluble in metatoluene dii'socyanate'for each "100 parts by weight of'the meta-toluene diisocyanate.

3. "The cellular reaction product of, on an approximate weight "basis; an alkyd resin having a water content of from 0.1% "to by weight prepared :from 4 mols trimethylol propane, 2.5 mols adipic acid "and-0.5mm phthalic anhydride and'having anacid numberoffromb to 80 from to 40 grams "of meta-toluene diisocyanate for each 30 grams of 'saidalkydzresin, '2 parts of ethyl cellulose having an ethoxyl-content of 45% to 49.5-% and a viscosity of from '50 to 100 centipolses for "each 100 parts of the-meta-toluene diisocyanate, the viscosity of the ethyl cellulose being determined on the basis of a 5% by weight solution :in a 60:40 toluene-ethanol solvent at 25 C., #and from 1 to '20 grams for each 30 grams of said alkyd resin of anyalkenyl ester ofan :aryl

.phesphonic acid :chosenirom the group consisting :of: diallyl phenyl phosphonate, bis r-(methallyl) benzene-phosphonate, diallyl toluene phosphonate.

L4. The cellular reaction productoi' an alkyd resin having a water content-20f from 0.1% tol5% by weight, an acid number of from 5 to 80 and wherein the hydroxyl and carboxyl groups of the alkyd resin reactants are in the ratio range of from 3(0'1-1) :1(COOH) to 4'(OH) :5('COOH),, from 35 to 150 parts by weight of meta-toluene diisocyanate for each 100 parts by weight "of said ethyl cellulose soluble in meta-'toluene-wdiisocyanate having acentipoise viscosity of between 7 and- 200 asdetermind on a"5% by weight solution in a 60:40 toluene-ethanol solvent at 25 'C., and an ethoxylcontentof from 43% to 50%.

5. The cellular reaction product of an alkyd resin ha ving a watercontent ofiroml0.1% to5% by weight, an acid number of from 5 to and wherein the hydroxyl and carboxyl groups of thealkyd resin reactants are in the ratio range of from 3(OH):I1-(COOH) 130 4(OH) 4510001'1), from 35 to "150 parts by weight of meta-toluene diisocyanateior each 100. parts by weight of said resin,--and from A; to 5 parts by Weight of ethyl cellulose foreach'l-OO parts by weight of themetatoluene diisocyanate, the ethyl cellulose being soluble in meta-toluene ldiisocyanate -and having a centipoise viscosity of between 50 and '100 as determinedon a 51% by weightlsolution in a 60:40

toluene-ethanol solvent at 25 C. and having an ethoxyl content of between 45% and 495%.

:6. The cellular reaction product of an alkyd resin having a water content of from 0.1% .to 5% by weight, an acid-number of from '5 to 80 and wherein the hydroxyl" and carboxyl groups of the alkyd resin reactants are in the ratio range of from S-(OH) 1 (COOH) to 4(0H) :5(COOH), from 35 to 7150 parts by weight of meta-toluene diisocyanate for each 100 parts by weight of saidJalkyd resin, from 1 to 20 parts by weight for each 30 parts by weight of said alkydresin of an alkenyl ester of .-an arylphcsphonic acid chosen .from the group consisting of diallyl phenyl phosphonate,

bis -.(methally-l) benzenephosphonate, diallyl toluene phosphonate, and approximately 2 parts' by Weight for each 100 par-tsby weight ofthe metatoluene ;diisocyanate-of a thermoplastic polymeric film-former soluble in meta-toluene diisocyanate chosen from the group consisting of: ethyl cellulose, polymeric chlorinated natural rubber, benzyl cellulose, vinyl chlorideevinyl acetate copolymer (from 87% to vinylchloride), polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polystyrene, polydichlorostyrene, polymeric methyl methacrylate, polymeric propyl methacrylate, polymeric isobutylmethacrylate, polymeric butyl methacrylate, co-polymer of methyl acrylate and ethyl methacrylate natural rubber. TI. The cellular reaction product of, on an approx-imate weight basis; \ana1kyd resin having a water. content of from 0.1% -to 5% by weight prepared from 4 mols trimethylol propane, 2{5 mols adipic acid and 0.5 mol phthalic anhydr-ide and having an acid number of from 5 to :80; from'l0 to 40 grams ofimeta -toluenediisocyanate'ioreach 30 grams of said alkyd resin,-from 1 to 20 par-ts by weight for each 30 parts by Weight of said alkyd resin of :an alkenyl ester of an aryl .phosphonic :acid chosen from the group consisting of: diallyl phenyl phosphonate, bis (lmethally l) benzenephosphonate, diallyl toluene phosphonate, andapproximatelyz parts by weight for each parts by weight of the meta-toluene di isocyanate of-a thermoplastic polymeric film-former soluble in meta-toluene diisoc-yanate chosen from the group consisting of: ethyl cellulose, polymeric chlorinated natural rubber, benzyl cellulose, vinyl chloride-vinyl acetateco-polymer (from -8' 7% to 95% vinyl chloride) polyvinyl chloride, polyvinyl acetate, polyvinyl butyra-l, polystyrene, polydichlorostyrene, polymeric methyl methacrylate,

polymeric propyl methacrylate, polymeric :iSObll" ass-seer V l9 co-polymer of methyl acrylate and ethyl methacrylate natural rubber.

8. The cellular reaction product of, on an approximate weight basis; an alkyd resin having a water content of from 0.1% to by weight prepared from 4 mols trimethylol propane, 2.5 mols adipic acid and 0.5 mol phthalic anhydride and having an acid number of from 5 to 80; from to 40 grams of meta-toluene diisocyanate for each 30 grams of said alkyd resin, from 1 to 20 grams for each30 grams of said alkyd resin of an alkenyl ester of an aryl phosphonic acid chosen from the group consisting of diallyl phenyl phosphonate, bis (methallyl) benzenephosphonate, diallyl toluene phosphonate. from 0.03 to parts by weight of ethyl cellulose soluble in meta-toluene diisocyanate for each 100 parts by weight of the meta-toluene diisocyanate.

9. The cellular reaction product of, on an approximate weight basis; an alkyd resin having a water content of from 0.19% to 5% by weight prepared from 4 mols trimethylol propane, 2.5 mols adipic acid and. 0.5 mol phthalic anhydride and having an acid number of from 5 to 80; from 10 to 40 grams of meta-toluene diisocyanate for each 30 grams of said alkyd resin, from 1 to grams for each 30 grams of said alkyd resin of diallyl phenyl phosphonate. from 0.03 to 15 parts by weight of ethyl cellulose soluble in meta-toluene diisocyanate for each 100 parts by weight of the meta-toluene diisocyanate.

10. The cellular reaction product of, on an approximate weight basis; an alkyd resin having a water content of iron- 0.1% to 5% by weight prepared from 4 mols trimethylol propane, 2.5 mols adipic acid and 0.5 mol phthalic anhydride and having an acid number of from 5 to 80; from 10 to 40 grams of meta-toluene diisocyanate for each 30 grams of said alkyd resin, from 0.03 to 15 parts by weight of ethyl cellulose soluble in meta-toluene diisocyanate for each 100 parts by weight of the meta-toluene diisocyanate, and a small amount of a metallic soap powder chosen from the group consisting of: zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, strontium stearate, magnesium hydroxy stearate, barium stearate, zinc laurate, calcium oleate.

11. The cellular reaction product of an alkyd resin having a water content of from 0.1% to 5% by weight, an acid number of from 5 to-80 and wherein the hydroxyl and carboxyl groups of the alkyd resin reactants are in the ratio range of from 3(OH):1(COOH) to 4(OH):5(COOH),

from 35 to 150 parts by weight of meta-toluene diisocyanate for each 100 parts by weight of said resin, from 0.03 to 15 parts by weight of ethyl cellulose soluble in meta-toluene diisocyanate for each 100 parts by weight of the meta-toluene diisocyanate, and from to 7.5 parts by weight for each 30 parts by weight of said alkyd resin of a metallic leafing powder chosen from the group consisting of aluminum leafing powder, aluminum bronze leafing powder, gold bronze leafing powder, copper bronze leafing powder, lead leaf-' lng powder, nickel leafing powder, silver leafingpowder, gold leafing powder, copper leafing powder, stainless steel leafing powder (18:8 chromium-nickel).

12. The cellular reaction product of an alkyd resin having a water content of from 0.1% to 5% by weight, an acid number of from 5 to 80 and wherein the hydroxyl and carboxyl-groups of the alkyd resin reactants are in the ratio range of from 3(OH) :1(COOH) to 4(OH) :5 (COOH) diisocyanate for each 30 parts by weight of said alkyd resin, from 0.005 to 0.015 parts by weight of ethyl cellulose soluble in meta-toluene diisocyanate for each 30 parts by weight of'said alkyd resin, and approximately 2 parts by weight for each 30 parts by weight of said alkyd resin of a metallic leafing powder chosen from the group consisting of: aluminum leafing powder, aluminum bronze leafing powder, gold bronze leafing powder, copper bronze leafing powder, lead leafing powder, nickel leafing powder, silver leafing powder, gold leafing powder, copper leafing powder, stainless steel leafing powder (18:8 chromiumnickel) 13. The cellular reaction product of an alkyd resinhaving awater content of from 0.1% to 5% by weight, an acid number of from 5 to and wherein the hydroxyl and carboxyl groups of the alkyd resin reactants are in the ratio range of from 3(OH :1(COOH) to 4(OH) :5(COOH), approximately 20 parts by weight of meta-toluene diisocyanate for each 30 parts by weight of said alkyd resin, from 0.005 to 0.015 parts by weight of ethyl cellulose soluble in meta-toluene diisocyanate for each 30 parts by weight of said alkyd resin, approximatell 5 parts by weight of diallyl phenyl phosphoriate for each 30 parts by weight of said resin, 2. small amount of benzoyl peroxide, and approximately 2 parts by weight for each 30 parts by weight of said alkyd resin of a metallic leafing powder chosen from the group consisting of aluminum leafing powder, aluminum bronze leafing powder, gold bronze leafing powder, copperleafing powder, copper bronze leafing powder, lead leafing powder, nickel leafing powder, silver leafing powder, gold leafing powder, stainless steel leafing powder (18:8 chromium-nickel).

. 14. The reaction product of an alkyd resin having a water content of from 0.1 %'*to 5% by weight, an acid number of from 5 to 80 and wherein the hydroxyl and carboxyl groups of the alkyd resin'reactants are in the ratio range of from 3(OH):1(COOH) to 4(OH) :5(COOH), from 35 to 150 parts by weight of .meta-toluene diisocyanate for each parts by weight of said resin, and from 5 to 20 parts by weight of polymeric chlorinated natural rubber for each 100 parts by weight of the meta-toluene diisocyanate, from 1 to 20 parts by weight for each 30 parts by weight of .said alkyd resin of a fire retardant alkenyl ester of aryl phosphonic acid additive chosen from the group consisting of: diallyl phenyl phosphonate bis (methallyl) benzenephosphonate diallyl toluene phosphonate.

15. The cellular reaction product of, on an approximate weight basis; an alkyd resin having a watercontent of from 0.1% to 5% by weight:

prepared from 4 mols trimethylol propane, 2.5 mols adipic acid and 0.5 mol phthalic anhydride and having an acid number of from 5 to 80; from 10 to 40 grams of meta-toluene diisocyanate for each 30 grams-of said alkyd resin, from 5 to '2 0 grams of polymeric chlorinated natural rubber having a centipoise viscosity of about-10 for each 100 grams of the meta-toluene diisocyanate, determined by using 20% by weight of the resin in toluene at 25 C., and about 5 grams of diallyl phenyl phosphonate for each 30 grams of said alkyd resin.

16. The reaction'product of an alkyd resin having a water content of from 0.1% to 5% by weight, an'acid number of .from 5 to 80 and and wherein the hydroxyl and carboxyl groups of the alkyd resin reactants are in the ratio range-,oi-irom 3(OH) :1(COOH) to 4mm (coon) resin of a fire retardant ,alkenyl ester'of aryl' phosphonic acid additive chosen from the group consisting of: diallyl phenyl phosphonate bis (methallyl) benzenephosphonate diallyl toluene phosphonate.

17. The cellular reaction product of, on an approximate weight basis; an alkyd resin having a water content of from 0.1% to 5% by weight prepared from 4 mols trimethylol propane, 2.5 mols adipic acid and 0.5 mol phthalic anhydride and having an acid number of from 5 to 80; from to 40 grams of meta-toluene diisocyanate for each 30 grams of said alkyd resin, approximately 5 grams of diallyl phenyl phosphonate for each 30 grams of said resin, and approximately 4 grams oi benzyl cellulose for each 100 grams of the meta-toluene diisocyanate.

18. The cellular reaction product of, on an approximate weight basis; 60 grams of an alkyd resin having a water content of about 0.85% by weight, an acid number of about 20 prepared from 4 mols trimethylol propane, 2.5 mols adipic acid, and 0.5 mol phthalic anhydride, 40 grams meta-toluene diisocyanate containing 2 grams ethyl cellulose of from 50 to 100 centipoise viscosity, as determined from a 5% by weightsolution of the ethyl cellulose in a 60:40 tolueneethanol solvent at 25 C., and having from 45 to 49.5% ethoxyl content for each 100 grams of the meta-toluene diisocyanate, the ethyl cellulose being soluble in meta-toluene diisocyanate, and 10 grams diallyl phenyl phosphonate.

19. The cellular reaction product of, on an approximate weight basis; 60 grams of an alkyd resin having a water content of about 0.85% by weight, an acid number of about 20 prepared from 4 mols trimethylol propane, 2.5 mols adipic acid, and. 0.5 mol phthalic anhydride, 40 grams meta-toluene diisocyanate containing 2 grams ethyl cellulose of from 50 to 100 centipoise viscosity, as determined from a 5% by weight solution of the ethyl cellulose in a 60:40 tolueneethanol solvent at 25 0., and having from 45 to 49.5% ethoxyl content for each 100 grams of the metatoluene diisocyanate, the ethyl cellulose being soluble in meta-toluene diisocyanate, 10 grams diallyl phenyl phosphonate, and 0.5 gram benzoyl peroxide.

20. The method of making cellular plastic which comprises providing an alkyd resin having an acid number of from 5 to 80 and a water content of from 0.1% to 5% by weight and wherein the'hydroxyl and carboxyl groups in the alkyd resin reactants are in the ratio range of from 3(OH) :1(COOH) to 4(OH) :5(COOH), mixing said alkyd resin and from 35 to 150 parts by weight of meta-toluene diisocyanate for each.

100 parts by weight of said alkyd resin and from 0.03 to parts by weight of ethyl cellulose soluble in meta-toluene diisocyanate for each 100 parts of the meta-toluene diisocyanate, and then allowing the resultant mixture to react.

21. The method of making cellular plastic which comprises providing an alkyd resin having an acid number of gfrom :5 ate .80 and. a water eerie.

tent of from 0.1% to :'5%-by weightand wherein the hydroxyl and carboxyl groups in the alkyd resin reactants are in the ratio range of from 3(OH):1(COOH) to 4(OH):5(COOI-I), mixing said alkyd resin andfrom 35 to 150 parts by weight of meta-toluene diisocyanate for each 100 parts by weight of said alkydresin, from'sl to 20 parts by weightfor each 30 parts by weight of said alkyd resin of a fire retardant alkenyl ester of arylphosphonic acid additive chosen from *the group consisting of: diallyl phenyl phosphonate', bis (methallyl) 'benzenephosphonate, diallyltoluene phosphonate, and a small amount of a thermoplastic film-forming polymer solubleln.meta-toluene diisocyanate, and then allowing the resultant mixture to react.

22. The method of making cellular plastic which comprises providing an alkyd resin having an acid numbefof from 5 to and a water content of from, 0.1% to 5% by weight and wherein the hydroxyl and carboxyl groups in the alkyd resin reactants are in the ratio range of from 3(OH):1(COOH) to 4(OH):5(COOH), mixing said alkyd resin and from 35 to 150 parts by weight of meta-toluene diisocyanate for each parts by weight of said alkyd resin and approximately 2 partsfor each 100 parts of the meta-toluene diisocyanate of ethyl cellulose having a centipoise viscosity of from 50 to 100 as determined from a 5% by weight solution of the ethyl cellulose in a 60:40 toluene-ethanol solvent at 25 C., and having an ethoxyl content of from 45% to 49.5% and soluble in meta-toluene diisocyanate, and then allowing the resultant mixture to react.

23. The cellular reaction product of, on an approximate weight basis; an alkyd resin having a water content of from 0.1% to 5% by weight, an acid number of from 5 to 80 and wherein the hydroxyl and carboxyl groups of the alkyd resin reactants are in the ratio of from 3(OH) :1(COOH) to 4(OH) :5(COOH), from 35 to parts of meta-toluene diisocyanate for each 100 parts of said resin, from 1 to 20 parts of diallyl phenyl phosphonate for each 30 parts of said resin, from 0.03 to 15 parts of ethyl cellulose soluble in meta-toluene diisocyanate for each 100 parts of the meta-toluene diisocyanate, and a small amount of a metallic soap powder chosen from the group consisting of: zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, strontium stearate, magnesium hydroxy stearate, barium stearate, zinc laurate, calcium oleate.

24. The cellular reaction product of, on an approximate weight basis; an alkyd resin having a water content of from 0.1% to 5% by weight, an acid number of from 5 to 80 and wherein the hydroxyl and carboxyl groups of the alkyd resin reactants are in the ratio of fromeach 100 parts of said resin, from 1 to 20 parts of diallyl. phenyl phosphonate for each 30 parts of said resin, from 0.03 to 15 parts of ethyl cellulose soluble in meta-toluene diisocyanate for each 100 parts of the meta-toluene diisocyanate,

23' copperleafing' powder, stainlesssteel leafing powder (18:8 chromium-nickel) l ELI SIMON.

FRANK W. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 24 r FOREIGN PATEN'I'S, v

Number Country Date 111,120 Australia. Of 1940 OTHER REFERENCES 10 2nd ed., p. 9 and 10, published 1936 by Remhold Pub. Corp. N. Y.

Ethocel Handbook: pp. 4 and 5; published 1940 by Dow Chem. Co., Midland, Mich. 

21. THE METHOD OF MAKING CELLULAR PLASTIC WHICH COMPRISES PROVIDING AN ALKYL RESIN HAVING AN ACID NUMBER OF FROM 5 TO 80 AND A WATER CONTENT OF FROM 0.1% TO 5% BY WEIGHT AND WHEREIN THE HYDROXYL AND CARBOXYL GROUP IN THE ALKYD RESIN REACTANTS ARE IN THE RATIO RANGE OF FROM 3(OH):1(COOH) TO 4(OH):5(COOH), MIXING SAID ALKYD RESIN AND FROM 35 TO 150 PARTS BY WEIGHT OF META-TOLUENE DIISOCYANATE FOR EACH 100 PARTS BY WEIGHT OF SAID ALKYD RESIN, FROM 1 TO 20 PARTS BY WEIGHT FOR EACH 30 PARTS BY WEIGHT OF SAID ALKYD RESIN OF A FIRE RETARDANT ALKENYL ESTER OF ARYLPHOSPHONIC ACID ADDITIVE CHOSEN FROM THE GROUP CONSISTING OF: DIALLYL PHENYL PHOSPHONATE, BIS (METHALLYL) BENZENEPHOSPHONATE, DIALLYL TOLUENE PHOSPHONATE, AND A SMALL AMOUNT OF A THERMOPLASTIC FILM-FORMING POLYMER SOLUBLE IN META-TOLUENE DIISOCYANATE, AND THEN ALLOWING THE RESULTANT MIXTURE TO REACT. 